F-actin vs actin

F-actin and actin both are nouns.

Word	Noun	Adjective	Verb	Adverb
F-actin	Yes	No	No	No
actin	Yes	No	No	No

As nouns, actin is a hypernym of F-actin; that is, actin is a word with a broader meaning than F-actin:

F-actin: a filamentous form of actin.
actin: one of the proteins into which actomyosin can be split; can exist in either a globular or a fibrous form

F-actin (noun)	actin (noun)
a filamentous form of actin.	one of the proteins into which actomyosin can be split; can exist in either a globular or a fibrous form